The Los Angeles Rams suffered their third loss in four games against the division-rival 49ers on Sunday, falling 31-14 as the team failed to score more than 14 points for the fourth straight game. But their biggest loss may have come in the form of reigning Offensive Player of the Year Cooper Kupp, who left the game with under two minutes to go in the game with an ankle injury.

Kupp appeared to be rolled up on while being tackled during a pass play on third down, with the game well out of reach. The All-Pro receiver remained down on the field for several moments, and the Rams surrendered when the game finally resumed, running the ball and kneeling to end the game.

After the game, Rams head coach Sean McVay admitted he made a mistake by keeping his best player in a game that was already decided.

“That’s why you wanted to try to be smart getting out of the game. And I’m kicking myself for not running the football again,” McVay said in his postgame presser. “But, I’m hopeful that he’s OK.”

Per NBC Los Angeles, Kupp had his ankle wrapped in the postgame locker room and was “noticeably limping.”

The blowout loss to San Francisco at SoFi Stadium dropped the Rams to 3-4 following their Super Bowl season, and if Kupp has to miss time they face a significantly more difficult road back to the playoffs. The 29-year-old receiver has accounted for more than 32 percent of the Rams’ total yards and six of their 13 total offensive touchdowns on the season. Even with Kupp, Los Angeles is third-to-last in the NFL in total yards and fifth-to-last in points.

In Week 9, they travel to Tampa to face another disappointing NFC team in the Buccaneers. Tampa Bay still has the fifth-best defensive DVOA (defense-adjusted value over average) in the league, per Football Outsiders, so it will be a tough.